Floating buffer self-aligning electrical connector



2,954,542 ELCATINC BUFFER SELF-ALICNINC ELECTRICAL CONNECTOR Filed Jan.11, 196C N. B. WALES Sept. 27, 1960 2 Sheets-Sheet 2 INVENTOR FLOATINGBUFFER SELF-ALIGNING ELECTRICAL CONNECTOR Nathaniel Bjwaies, sothamptn,N Y.

mea aan. 11, 1960, ser. No.1,s91 s claims. (ci. 339-64) This inventionrelates to a separable electrical connector in which a floatingself-aligning captive buifer member resiliently interconnects twoidentical cable terminating members on spherical contacting surfaces.

y Many advantages result from this step beyond the existing connectorart. In the present connector -art it is conventional to use a maleterminal member associated with one connector body and a female terminalassociated with a second directly mating connector body. One or both ofthese terminals are made to be resilient to supply the necessary contactpressure. This leads to the contrary metallurgical requirement that aterminal be at once resilient ,and `at the same time malleable (in thecase of crimp type terminals), or, resilient and capable of beingsubjected to heat without losing its resiliency (in the case of soldertype connectors). My invention overcomes these limitations by the use ofa resilient oating buffer member which engages two identicalnon-resilient terminal members at its opposite ends, thus allowing thematerial comprising the terminal members to be chosen to be the optimummaterial `for the connecting method used, whether solder or crimp type,and allowing the material comprising the buffer member to be chosen tobe the optimum material for resiliency in maintaining contact pressure,since this buifer member, being separate, need never be subjected 4tosoldering levels of temperature, or to crimping deformations.

My invention teaches the use of spherical areas of contact between .thefloating -buifer member and the terminal members so that the butermember may align itself automatically in the manner of la universaljoint so as to com pensate for any limited misalignment of the terminalmembers to be connected. This self-aligning feature thus makes possiblethe use of multiple-connector hermetically sealed terminal plates whichrigidly hold land are bonded to their terminals, even through thecorresponding terminals are not in perfect alignment due tomanufacturing tolerances.

In addition, this tloating buffer construction removes a major cause `ofconnector -failure by substantially obviating the vibratory stressessuered by directly mating terminals.

In the preferred form of this invention, the buffer member is a doublyfemale member which resiliently embraces two male non-resilientspherically surfaced terminal members at its two opposite ends. Thispermits the use of sheet metal stamping and forming techniques in themanufacture of these spring buffer connectors.

However, within the scope of my invention it is equally feasible to usea doubly male, resilient, spherically sur faced buffer member internallyengaging two female, cylindrical, non-resilient terminal members at eachof its ends.

It is a characteristic of this invention that the foregoing resilientbuffer members are provided with means for hold-ing them captive in afree-floating manner with respect to one of the two separableconnectors.

`My invention discloses a gang locking plate means for retaining all ofthe terminal members within the body of ICC a connector plug. In thisway, the cable wires can be connected to the terminal members at anunconned work station, and then inserted into the connector plug body,`where a single actuation of the said gang locking `plate will secure allsuch terminals simultaneously. i

This technique insures a superior opportunity for inspection or repair,and minimizes the fabrication labor for cable and connector assembly.

A feature of this disclosure also `provides a dual purposekey memberwhich serves both as a polarizing key and as a sub-assembly securancemeans whereby the said gang locking plate is slideably secured to aconnector plug -body for ease of terminal assembly.

One object of my invention is to provide a connector design affordingeconomy of manufacture `and a superior degree of reliability.

A second object is to provide self-aligning means to make possible theseparable interconnection of multiple rigidly bonded terminals.

A third object is to disclose a method of separable elec-` tricalinterconnection which minimizes the stresses on its terminals.

` A fourth object is to provide a design of connector plugs whichpermits the `simultaneo-us locking or unlocking of an 'array ofterminals to a connector plug by the displaceinent of a single unitarygang locking member.

Other objects are implicit -in the following specifications and claims.

In the drawings: Y Figure l is a section in transverse elevation throughthe laxis of a preferred embodiment of my invention;

Figure 2 is a longitudinal section through 2 2 of Fig. l;

Figure 3 is an alternative forml of my invention showing its applicationto an hermetically sealed type of connector; and

Figure 4 is an alternative form of the connection means of my inventionshowing the inverse type of floating resilient buffer connector.

Referring to Figs. 1 and 2 it may be seen that the separable connectorillustrated consists of two facing sets of eighteen identical terminals2, one set of which is positioned by the cylindrical insulating plu-g 8within the female cable shell 4, while the other set is positioned by anidentical insulating plug 8 within the male chassismounted shell 6.

Each terminal, 2, is provided with la cavity 36 into which the bared endof its cable wire may be either crimped or soldered. The terminals 2'are each provided with an annular locking groove 35 into which theygang insulating locking plates 9 may be engaged to constrain eachterminal 2 within its insulating positioning 'block 8 or 8.

The floating ibuer connectors 1 of this embodiment consist of springmetal semi-cylinders formed 4from sheet metal land provided with anequatorial slot 18 which serves both to provide means to constrain thebuffer connector within its insulating mounting plates 3 and 37, and tomake its two spring Contact pressure actions independently table tograsp the spherically shaped outer ends of terminals 2 Aat either end.Thus, the evolved shape of the stampings from which buffer members 1`are formed may be seen to have an H configuration.

, The holes 17 in gang locking plate 3 are congruent with thecorresponding holes 41 -in the buffer retaining plate 31. However, whenthe holes 17 and 41 are placed in congruence, the circular peripheriesof the corresponding plates 3 and 37 respectively are eccentric withrespect to one another. This condition can occur only when the bufferassembly is removed from the constraint of shell 4, and it is in thiscondition that the buffer members 1 are inserted during assembly of theplug and while holes '17 and 41 are concentric. After insertion ofbuffer springs 1 through both plates 3' and 37 (preferably in, a

Patented Sept. 27, 1960 jig), the plate 3 is displaced radially withrespect to plate 37'so 'that-their outer peripheries are concentric asVin Figs. 1 and 2. This causes the lower lips of holes 17 to enter theequatorial slots 18 of buffer springs l thereby loosely entrappingthemand allowing thisfsub-assembly toibeinserted'into the shell 4,untilseated against retaining shoulder 39 of shell 4 as shown in Fig. 2. Aninternal keyS integral with shell 4 assures the phasing of plates 3 and37 withrespect to one anotherA and with respect-to the terminal bodyplug 8 which also engages key 5,.

"The eighteen terminal members 2 ofshell 4 are retained within theirinsulating positioning block 8 by means of the insulatinglgang lockingplate 9 which has ageometry with respect to block 8 similar to thegeometrical relation between plates 3 and 37 as previously described. Inaddition, a retaining metal `key 20 is provided so that when key 20 isinserted into mating slot 42 of 4block 8 and into slot 43 of plate 9,the bending down oftabs 21 and 22 which a-re integral with key 20, willform a subassembly in which plate 9 is slideably retained against theface of block 8. Thus, when sub-assembly 2-8-20 is removed from shell 4,the gang locking plate 9 may be slideably displaced with respect toblock 8, under the constraint of key 20 and tabs 21 and 22, until thelocking holes 10 of plate 9 are concentric with the terminal cavities 44of block 8. In this condition, terminals '2 with their attached cablewires (not shown) may be either inserted or removed.

After the insertion of terminals 2 into this sub-assembly, plate 9 canbe slideably displaced relative to block 8 until their outer peripheriesare concentric. This will cause the upper lips of holes 10 to engage theannular grooves 35 of terminal members 2 thereby simultaneouslylockingall pins 2 to block 8.

The sub-assembly of the female cable shell 4 is comcompleted byinserting the foregoing sub-assembly 2--8-9-20 into shell 4 and againstthe insulating split spacing ring 16 Where it is locked by the snap ring12 which engages an internal groove inshell 4. During the foregoing nalassembly, the outer spherical surfaces 46 of terminal members 2 wereeach caused to enter and expand the corresponding left semi-cylindricalfemale ends of the floating spring buler member 1 thereby setting upgood electrical contact pressure between each terminal 2 and its bufferil. The female cableplug is completed by a bell iitting31 which securesto shell 4 by screw threads 34, and-by a compression fitting 30 whichcan distort rubber grommet 13 to cable clamping position 13 when it isscrewed into the' threads 32 in bell 31. It is to be noted that thedesign of grommet 13 is such that its internal dilation is due tocantilever bending primarily, and to compressional Volumetric distortionin only a secondary degree. This allows'for a wider accommodation ofcable diameters than would be possible if only volumetric dilation wereused to clamp the cable.

lThe male chassis plug consists of shell 6 with the square integralmounting flange 14, into which the terminal positioning block 8', thegang locking plate 9', and the male terminals 2 are assembled againstshoulder 40 by means of snap ring 11 in an identical manner to theassembly of the corresponding parts pertaining to shell 4.

Internal key 7 integral with shell 6 assures the phasing of sub-assembly8-9 with respect to the mounting ange ears 14. yThe .sub-assembly key 19with its locking tabs 23 `and '24 may be seen to be identical to thelocking key 20 and its tabs'22 and21 except that the outer end has beenextended to form a` polarizing key capable of entering the mating slots47 in. plates 37 .and 3 of the female plug, but only when .the twoseparable plugs are properly aligned.

I'hefslotf45. of plug 8Y thus correspondsto slot 42 of plug 8, -and slotf40r of1`plate'9' corresponds to. slot 43 of platef 9.

The screw threads 33 of shell 6 allow the mating threads in knurledsleeve 15 'to lock the two separable shells 4 and 6` together afterftheentrance of the spheri cally surfaced heads 46 of terminal members 2into the unoccupied ends of the spring buer clips 1.

It is evident that the cylindrical bodies of buffer 1 can now take uppositions which are-.not parallel to the cornmon axis of the two shells4 and 6 to accommodate any i' departures .strom eeaxialityl .between thecorresponding terminal membersluandfz'..dueboth -to the looseness ofconstraintAprovidedbyslots 18 .and Ato the spherical surfaces of contactprovided at both ends of the buffer members1.""TIhis:accommodation.isaceomplished under constant contact pressureatvsurfaces 46, and, since the buffer members '1 can transmit negligiblebending stress to their terminal members 2 due to this geometry ofaccommodation and the frictional nature of engagement. The terminals 2and their associated wires are thus very largely strain free.

Figure 3 serves both to illustrate the geometery `of accommodationbetween non-coaxial terminal members afforded by my resilient buffermembers, and to illustrate an .alternative construction of such a buffermember within the scope of my invention.

In Fig. 3 the buffer 1 is turnedby a lathe from a resilient metal so asto comprise a hollow cylindrical sleeve 'having a retaining shoulder 26.rThe outer portions ofthe sleeve are then ,slotted by slots 25 so as toform two independently resilient cavities capable of embracing thespherical Vsurfaces 46 of the male terminal members 2 and 2 ateitherend.

Shoulders 26.are loosely trapped within the cavities 49 of theinsulating plates 27 and 28 to form the buffer sub-assembly. Theterminals 2 and 2 of Fig. 3 are shown to be bonded to the ceramic plates29 and 29', respectively, to form a rigid hermetic seal. These tworigidly supported terminals 2 and 2 are shown to be approximatelyparallel but non-coaxial by the displacement D such as that which mightbe due to manufacturing inaccuracies. Nevertheless, the buffering action`of sleeve 1 due to the universal jointing action afforded by the twokspherical contacting surfaces 46 .still allows perfect pressuredelectrical connection between terminals 2 and 2', while at the same timepreventing any except negligible bending strains to be imposed on therigid bonds to ceramic sealing plates 29 and 29'.

If it is desired to construct a hermetic seal such as that of Fig. 3,but Without any soldered joints at all, it is evidentlyvpossible vtomake each male member 2 double ended so as to have an identicalspherical surface 46 on each side of sealing plate 29 or 29' therebypermitting the use of a male cable assembly with crimp type terminalssuch as that of shell 4, Fig. 2, on each side of the hermetic seal.

Figure 4 illustrates the inverted form of my invention in which Vtheresilient buffer member still contacts identical terminal members onspherical contact surfaces at either end, but in which the buffer member1 consists of a doubly male dumbbell shaped metal turning which is splitby slots 38 on either end to provide independent resilient sphericallysurfaced contacts. The plates 3 ,and 37 serve to loosely constrain thebuifer as before. In this case the terminal members 2 are provided withthe cylindrical nonresilient female cavities 50 to engage the resilientbuffer l members 1.

What I- claim is:

l. In a separable electrical connector, the combination comprising a rstplurality of metal terminal members, a groove in each of said firstterminal members, a second plurality of metal terminal members, a groovein each of said second terminal members, a plurality of elongatedtwo-ended metal buffer members each resiliently contacting one of saidfirst terminal members at one of its said ends lon a first partiallyspherical contact surface and resilientlyVv contacting` oneof saidvsecond terminals at its other said end on a second partially sphericalcontact surface, a first insulating terminal block for locating said rstplurality of terminal members in spaced relation to one another, a rstinsulating gang locking plate having apertures adapted simultaneously toengage said first grooves, a rst means for constraining said firstlocking plate relative to said first terminal block whereby said firstapertures are in engaged relation to said first grooves, a secondinsulating terminal block for locating said second plurality of terminalmembers in spaced relation to one another, a second gang locking platehaving apertures adapted simultaneously to engage said second grooves, asecond means for constraining said second locking plate relative to saidsecond terminal block whereby said second apertures are in engagedrelation to said second grooves, and means for loosely constraining saidbuffer members in spaced relation to said tirst insulating terminalblock.

2. In a connector in accordance with claim 1, means to retain said firstgang locking plate n sliding constraint with respect to said firstterminal block, and combination means both to retain said second ganglocking plate in sliding constraint with respect to said second terminalblock and to polarize the engagement of said second plurality ofterminals with the corresponding said plurality of buffer members.

3. In a separable connector, the combination comprising a firstplurality of terminal members each having a partially spherical contactsurface, a second plurality of terminal members each having a partiallyspherical contact surface, a first insulating terminal block forlocating said first plurality of terminal members in spaced relation toone another, a second insulating terminal block for locating said secondplurality of terminal members in spaced relation to one another, aplurality of unitary buffer members each formed from an H-shaped springmetal blank so as to possess two independent interconnected splitcylindrical female cavities for resiliently embracing one of thepartially spherical contact surface of said' rst plurality at one endand for resiliently embracing a corresponding one of the partiallyspherical contact surfaces of said second plurality at its other end, athird insulating block for loosely locating said buffer members inspaced relation to one another, and an apertured insulating plateadapted to enter each space between the said twov cylindrical cavitiesof each buffer member whereby to loosely restrain said buffer members inan axial direction with respect to said first and third insulatingblocks.

References Cited in the le of this patent UNITED STATES PATENTS1,531,917 French Mar. 31, 1925 2,086,424 Koehler July 6, 1937 2,606,233Schymik Aug. 5, 1952 2,658,183 Klostermann et al Nov. 3, 1953 FOREIGNPATENTS 533,310 Great Britain Feb. 11, 1941

